SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d388df4beb3b3b2b9bd254942e8ea9deb4316c79aa133e56f8f566b3ed12b73' 
  AND token = 'TNOq/pWV0BzMVOMlvzF+MjhJZoS7XBeyZ13bwAXpyj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}